- Updates function arguments

lib/Newsletter/Shortcodes/Categories/Link.php

@@ -8,10 +8,10 @@ use MailPoet\Subscription\Url as SubscriptionUrl;
 
 class Link {
   static function process($action,
-    $default_value = false,
+    $default_value,
     $newsletter,
     $subscriber,
-    $queue = false
+    $queue
   ) {
     switch($action) {
       case 'subscription_unsubscribe':

lib/Newsletter/Shortcodes/Categories/Newsletter.php

@@ -8,10 +8,10 @@ require_once(ABSPATH . "wp-includes/pluggable.php");
 
 class Newsletter {
   static function process($action,
-    $default_value = false,
+    $default_value,
     $newsletter,
     $subscriber,
-    $queue = false,
+    $queue,
     $content
   ) {
     switch($action) {

lib/Newsletter/Shortcodes/Categories/Subscriber.php

@@ -11,7 +11,7 @@ class Subscriber {
   static function process(
     $action,
     $default_value,
-    $newsletter = false,
+    $newsletter,
     $subscriber
   ) {
     if($subscriber !== false && !is_object($subscriber)) return false;